please ID this hitchhiker. Scared to put this frag in my tank!

Good point, if thats the case it may not be such a good thing. What kind of frag did you purchase? Any chance you have a sixline or melanarus wrasse in your tank?

 

nope. But it the coral I bought was sitting next to a big red sea apple.

 

no, no.. just inverts, a watchman goby and I just bought a pj cardinal

 

its just a rock with a bunch of different mushrooms and polyps on it

 

no that wouldnt make any difference. i would not chance it and throw the creatures in my sump.
had soft coral eating nudibranchs and could never figure out why my leather was suffering. untill one day i seen this little creature the same color as the coral

 

Try as best as you can do dip your corals whenever you bring them home. My LFS has these shots of Coral RX that I am going to start using. I never had dipped before and and starting to notice lots of unwanted hitchhikers. I wouldn't be too worried about dipping a little frag plug but when you get those rocks... Watch Out!

 

after some serious searching on Google and putting the little guy under a magnifying glass I'm quite certain it's a baby bristleworm and I've decided to add him to my CUC.
here's hoping...

 

If it's not a piece of a bristleworm, it's likely an epitoke, which is how BW's reproduce. Simply put, they grow the epitoke on their tails and it breaks off and makes its way around the tank, often swimming in a corkscrew motion.

 

i never knew that. interesting

 

I thought bristle too...bristles creep me out so I'd get rid of it